Electronic Telegram No. 2453 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION CBAT Director: Daniel W. E. Green; Hoffman Lab 209; Harvard University; 20 Oxford St.; Cambridge, MA 02138; U.S.A. e-mail: cbatiau@eps.harvard.edu (alternate cbat@iau.org) URL http://www.cbat.eps.harvard.edu/index.html Prepared using the Tamkin Foundation Computer Network SUPERNOVAE 2010hd, 2010hg, AND 2010hj J. L. Prieto, Carnegie Observatories; and J. Fuentes, Las Campanas Observatory, report that they obtained optical spectra (range 380-920 nm; resolution 0.7 nm) of 2010hd (cf. CBET 2429), 2010hg (cf. CBET 2434), and 2010hj (cf. CBET 2438) on Sept. 10 UT with WFCCD mounted on the du Pont 2.5-m telescope at Las Campanas Observatory. The SNID cross-correlation software (Blondin and Tonry 2007, Ap.J. 666, 1024) was used to aid identification and age/redshift estimation. The spectrum of 2010hd resembles that of the type-IIn supernova 1998S at 72 days after discovery (see Fassia et al. 2001, MNRAS 325, 907); it is dominated by a strong, intermediate width (FWHM about 5600 km/s) H-alpha line in emission, He I and Fe II lines in absorption, and the Ca II near-infrared triplet in emission. SN 2010hg is a type-Ia supernova a couple days before maximum light; after correcting for the recession velocity of the host galaxy, NGC 3001 (2464 km/s; H I Parkes All-Sky Survey Final Catalog; Wong et al. 2006, MNRAS 371, 1855), a blueshift of the Si II (rest 635.5 nm) profile is measured to be 10000 km/s. The spectrum of 2010hj is that of a normal type-Ia supernova at approximately two months after maximum light; the redshift obtained by SNID from the supernova spectrum is z = 0.030 +/- 0.005. Additional unfiltered CCD magnitudes for 2010hg from L. A. G. Monard in Pretoria: Sept. 4.139 UT, 14.4; 5.138, 14.2; 6.140, 14.1; 7.136, 14.0; 8.138, 14.0; 9.137, 13.9. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2010 CBAT 2010 September 12 (CBET 2453) Daniel W. E. Green